This image is based on Alpine Linux image, which is only a 5MB image, and contains Bash (Bourne Again SHell) with some useful tools (e.g., complete implementations of grep, sed, awk, bc, head, tail, and etc).
This image is only 10MB on disk.
$ docker run --rm frolvlad/alpine-bash bash -c 'echo "Hello World"'
Once you have run this command you will get printed 'Hello World' from Bash!